Pilot Study: An Ocular Biomarker for Diagnosis of Attention Deficit Hyperactivity Disorder

Abstract

Objective Biomarkers of attention deficit hyperactivity disorder (ADHD) are crucial for early diagnosis and intervention, in which the identification of biomarkers in other areas of the body that represent the immature brain of children with ADHD is necessary. The present study aimed to find biomarkers of ADHD in the retina and assessed the relationship between macular thickness of the retina and cortical thickness of the brain in children with ADHD. Methods Twelve children with ADHD and 13 control children were recruited for the study. To find ocular markers of ADHD, we investigated the correlation between clinical symptoms of ADHD assessed with the Korean ADHD Rating Scale (K-ARS), cortical thickness of the brain, and macular thickness measured with the mean thickness from the Early Treatment Diabetic Retinopathy Study (ETDRS). Results Children with ADHD showed increased macular thicknesses quantified as an ETDRS ring in both eyes, compared to control subjects. Moreover, the right inner ETDRS ring had a positive correlation with K-ARS scores. The ADHD group had an increased ratio of thickness of the right frontal lobe to that of the parietal cortex, compared with the control group. There were positive correlations between the means of the inner ETDRS ring (right) and the left paracentral/right isthmus cingulate thicknesses in the control group. However, there were negative correlations between the means of the inner ETDRS ring (right) and the left frontal pole/right pars triangularis thicknesses in the ADHD group. The results of both groups were at the uncorrected level. Conclusion The different patterns of macular thickness might represent the immature cortical thickness of the brain in children with ADHD.

Assessment of intraocular pressure, macular thickness, retinal nerve fiber layer, and ganglion cell layer thicknesses: ocular parameters and optical coherence tomography findings in attention-deficit/hyperactivity disorder

“…In recent years, few studies have explored macular thickness in ADHD. 2,5 In line with our findings, a recent study analyzed macular thickness in children with ADHD and found no significant difference in the ADHD group as compared to controls. 5 However, in another study, Bae et al found increased macular thicknesses in the ADHD group.…”

“…Many scientists continue to search for biological markers that might guide the diagnosis of ADHD and elucidate its etiology. 2 For this purpose, researchers have frequently used different neuroendocrine and neuroimaging techniques to define particular abnormalities related to this disorder. [2][3][4][5] There is general agreement regarding the atypical brain structure findings associated with ADHD on neuroimaging.…”

“…2 For this purpose, researchers have frequently used different neuroendocrine and neuroimaging techniques to define particular abnormalities related to this disorder. [2][3][4][5] There is general agreement regarding the atypical brain structure findings associated with ADHD on neuroimaging. 6 Global decreases in total brain volume, most prominent in the prefrontal cortex, basal ganglia, cerebellum, and parietotemporal areas, have been reported in volumetric analyses.…”

“…Since the eyes are considered a prolongation of the central nervous system, peripheral biomarkers such as the retinal nerve fiber layer (RNFL) and macular thickness promise a fresh pathway into investigation of brain development. 2 A recent article outlined the significant benefits of a methodology using assessment of RNFL and macular thickness, which is particularly attractive considering the similarities between the brain and retina from an embryological point of view and the relatively simple and accessible nature of retinal examination compared to brain scans. 10,11 For centuries, the retina has been known to provide insight into the status of the brain, suggesting the suitability of retinal research to explore bipolar disorder, schizophrenia, major depressive disorder, and ADHD.…”

“…Notably, OCT has been used in a few studies to evaluate patients with ADHD. 2,5,15 Hergüner et al investigated macular thickness, macular volume, and RNFL thickness in children with ADHD and a control group. 5 They found lower RNFL thickness only in the nasal quadrant in a patient with ADHD compared to the control group; in the other quadrants, RNFL thickness was not significantly different.…”